Drowned rat first mammal wiped out by human-made climate change

Few people have heard of the Bramble Cay melomys, but its name could go down in history as the first mammal species to be wiped out through human-induced climate change.

As recently as 1978, hundreds of these rodents (Melomys rubicola) inhabited Bramble Cay, a tiny island that forms part of the Great Barrier Reef. But there have been no sightings of the animal since 2009, and a comprehensive survey of the island has now confirmed the worst.

Despite leaving small mammal traps across Bramble Cay – which is only the length of three football pitches – for 900 nights, none were caught. Camera traps operating for 60 nights found no sign of the rodent either.

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“Significantly, this probably represents the first recorded mammalian extinction due to anthropogenic climate change,” said Luke Leung of the University of Queensland’s school of agriculture, and a member of the team whose survey report was published this week.

Leung and his colleagues believe the rodent was the victim of rising sea levels that inundated the island on multiple occasions and probably drowned many of the animals.

First of many?

“As far as I’m aware, it’s the first case where climate change has been the principal factor behind a mammal species’ demise,” says Richard Thomas of TRAFFIC, the organisation that monitors trade in endangered species. He says that there may have been other cases where climate change has contributed, but not been pivotal.

“There is almost no doubt the Bramble Cay melomys is extinct, and there is no doubt that this is caused by habitat loss due to sea level rise,” says James Watson of the University of Queensland.

The International Union for Conservation of Nature also said that the rat is probably the first to succumb to climate change. “No mammals have to date been listed as extinct due to climate change on the IUCN’s Red List of Threatened Species,” says Jamie Carr, leader of the IUCN Global Species Programme’s Climate Change Unit. “We have, unfortunately, been expecting this situation to change.”

Yet there is still hope for the Bramble Cay melomys. The species is thought to have originated in the Fly River delta of Papua New Guinea, and it is possible that it or a close relative still lives there. It may be premature to declare the rodent extinct on a global scale, said Leung.